Air-cooled tank for electrical apparatus.



APPLICATION FILED DEC-23.1913.

Patented Oct. 5, 1915.

WITNESSES:

flaw ATTORNEY4 FINITnD STATES PATENT OFFICE.

in ISAAC HARTER, 0]! NEW YORK, N. Y., ASSIGNOR TO THE BABCOCK & WILGOX COMPANY,

OF BAYONNE, JERSEY, A CORPORATION OF NEW JERSEY. I

AIR-COOLED TANK FOR ELECTRICAL APPARATUS.

Application filed December Q3, 1913. Serial No. 808,477.

'My invention relates to air-cooled tanks containing a fluid where it is desired to dissipate heat suppliedto the fluid by electrical apparatus contained in said tank, and to maintain the temperature of the fluid within certain working limits, and-has been designed more particularly for use as a tank for cooling transformer coils. Such tanks are ordinarily made either with plain or corrugated surfaces, the amount of surface being made large enough to produce suflicient cooling, or they are made with tubes inserted in the walls of the tank in such a manner as .to permit temperature differences in the different levels of the fluid to set up a circulation through the tubes and through the tank. The cooling effect of a tank of given outside dimenslons' can be made greater in a tank provided with cooling tubes than in a plain or corrugated tank, due to the facility with which the tube surface can be added to the tank, also because the fluid is divided into smaller bodies and again because convection currents of air rising among the tubes can more thoroughly reach the surface.

One of the disadvantagespf it tank 'con structed in the -ordinary,manner with circular cooling tubes is that radiation from the walls of the tank itself is largel prevented by the tubes unless the num er of such tubes is kept small. Another disadvantage is that if the diameter of the'tubes is increased to increase'the surface, the rate at which heat can be taken from the fluid which circulates through the tubes is decreased, so that in practice the tubes must necessarily be small in diameter and spaced closely together, which leads to'complication and increase in cost.

My invention relates to tanks provided with cooling tubes and consists in a particular form and arrangement of such tubes, and will be understood by reference to the accompanying drawings in which Figure 1 is a top view with some of the tubes in section; Fig. 2 a side elevation,

partly in section Fig. 3 a longitudinal tion, the tank being placed horizontalyantl Fig. 4: a horizontal section on the plane: of the line 44 of Fig. 2.

Similar reference numerals indicate lar parts in the several v1ews.

Referring to the drawings the'numerall designates a tank of suitable dimensions: and

be used, such as a transformer casing.

"Patented Oct. 5', 1915.

form for the apparatus for which it is to Tubes 2 are inserted into the walls of the tank, said tubes bein flattened in planes normal to the tank. he tubes are preferably vertical and extend from the lower to the upper end-of the tank and are fitted into openings 3 of the same section as the ends of the tubes. The construction shown in the drawings is the one preferred by me but it is obvious that the advantages incident to the flattened tube would still obtain, in a modified degree, if the tubes were flattened in part, or if they entered the tank at various angles and at various points. In transformers oil is the cooling medium, and to make tight joints the tubes may be welded to the tank.- The oil enters the upper parts fluid as exists with smaller circular tubes,

with the result that the rate at which heat is communicated from the fluid to the walls of the tubes will. not be decreased, as it would be should the large tubes be used without flattening them. A, further ad vantage is that for a given spacing of the flattened tubes more surface of the tank is exposed for radiation than. where round tubes are employed, and there is more free dom for circulation of air currents than exists with round tubes. A greater number of the flattened tubes can also be effectively attached to the tank with the tube holes entering at the same level than-with round tubes.

In. transformers it is highly essential that the heat produced by theielec'ti ic current be conveyed away as rapidly as formed, otherwise the temperature of the apparatus would increase and would finally reacha dangerous is greater than with round tubes.

of the surrounding air as possible, as the elliciency may be decreased through an increase in temperature. In a tank such as described I dispose the surface so as to obtain a maximum cooling" effect through combined radiation and conduction t0 the surrounding air, and thereby provide an apparatus which is particularly adaptable to the work it accomplishes.

By using tubes flattened or having their greatest axis on lines substantially normal or radial to the tank, the radiation from the tank walls for a given perimeter of a tank F urthermore, with two tanks of the same diameter and the same'amount of external tube cooling surface, the flattened arrangement gives a greater area between the tubes for the flow of convection air currents than with round tubes. For the same reason, there is a greater entrance and exit area for the upwardly flowing convection air currents at the junctures of the tubes with the tank. Again, there is a special advantage in using flattened tubes containing oil and exposed to the air for the reason that oil is relatively a poor conductor of heat and by flat tening the pipe the film of oil is thinner and the speed at the different points in the cross section is more nearly the same than in a circular pipe, thus aiding in heat transfer.

lVhat I claim and desire to secure by Letters Patent of the United States is 1. An air-cooled tank arranged to contain a fluid to dissipate heat from an electrical apparatus, said tank having connected to its walls a plurality of tubes exposed to the air and-through which the fluid circulates, the cross-sections of said tubes having axes of different lengths and the longest axes lying in planes substantially normal to the tank.

2. An air-cooled tank to contain a fluid to dissipate heat from an electrica apparatus, said tank having inserted in its walls a plurality of tubes through which the fluid circulates, said tubes having at least a portion whose cross section is flattened where they are acted on by the air. and disposed in planes substantially normal to the surface of said tank.

3. An air-cooled tank to contain a fluid 'to dissipate heat from anelectrical apparatus, said tank having inserted in its walls a plurality of tubes through which the fluid circulates, said tubes having at least a portion whose cross section is flattened where they are acted on by the air, and disposed about the tank in a substantially vertical position. I

4. An air-cooled tank arranged to contain a: fluid to dissipate heat from an electrical apparatus, said tank having connected to its walls a plurality of substantially vertical tubes exposed to the fair and through which the fluid circulates, the crosssections of said tubes having axes of different lengths and the longest axes lying in planes substantially normal to the tank.

5. A tank designed to dissipate heat from electrical apparatus, said tank having a plurality of flattened tubes projecting outwardly from its wall.

6. A tank designed to dissipate heat from electrical apparatus, said tank having a. plurality of tubes projecting outwardly therefrom and having at least a portion whose cross section is flattened.

In testimony whereof I have hereunto signed my name in the presence of two subscribing witnesses.

ISAAC HARTER. Witnesses:

E. P. TERRY, JOHN A. W. DIFIN. 

